Diaphragm for telephone receivers



1927' c. s. WIELAND DIAPHRAGM FOR TELEPHONE RECEIVERS Filed April 4, 1924 IN VENTOR Wham ATTORNEY Patented Aug. 16, 1927.

CHARLES G. WIELAND, OF NEW YORK, N. Y.

DIAPHRAGM FOR TELEPHONE RECEIVERS.

Application filed April 4,

This invention relates generally to diaphragms such as are used in telephone receivers.

As is known, the reproduction of the voice, or of sounds generally, in the telephone receiver is due to the vibration of a thin sheet or disk of iron which is placed adjacent the two ends of the usual horseshoe magnet, the disk being secured at its edges only so that it may be free to vibrate. The strength of the sound produced depends on the strength of the magnetic field around the poles of the magnet, the stronger the magnetic field the stronger the sound, and it is the purpose of the present invention to provide a construction which presents a mag netic field of increased strength, and which will better utilize the strength of the magnet. To strengthen the magnetic field it is necessary to put a larger mass of magnetic material such as iron opposite the poles of the magnet, and to do this I make use of a diaphragm presenting an increased amount of material at its centre, to produce a magnetic field of increased strength while at the same time preserving the essential flexibility of the diaphragm on the outer or marginal portion thereof.

For further comprehension of the invention, and of the objects and advantages thereof, reference will be had to the following description and accompanying drawing, and to the appended claim in which the various features of the invention are more particularly set forth.

Figs. 1 and 2 of the drawing are axial sectional views showing various embodiments of my improved diaphragm.

In the form of the invention shown in Fig. 1 of the drawing the drawing comprises a think disk 10 of suitable material such as iron which is of greater thickness adjacent the centre thereof than at the edge, this feature, broadly considered, being common to each form of diaphragm shown in the various views. In the form shown in Fig. 1 the diaphragm is flat on one face,

1924. Serial No. 704,131.

than the inner portion, 10 the diaphragm thus increasing rapidly in thickness toward the centre thereof.

The diaphragm 14 shown in Fig. 2 of the drawing is of a shape in axial section corresponding to two of the disks 10 with their flat faces in contact, this disk being comparatively thick at the centre and beveled off rapidly toward the edge.

I/Vhile I have shown the thickness of my improved telephone receiving diaphragms enlarged and described a preferred embodiment of my invention, it is to be understood that I do not limit myself to the precise construction herein disclosed, and the right is reserved to all changes and modification coming within the scope of the invention as defined in the appended claim.

Having thus described my invention,

what I claim as new and desire to protect by Letters Patent. of the United States is as follows In combination with the horseshoe magnets of telephone receivers, a diaphragm comprising a one-piece thin metal disk, a relatively th1ck mass of magnetic material signature.

CHARLES G. WIELAN D 

